1. Technical Field
The present invention relates to an optical disk drive and a pickup device, and in particular to an optical disk drive and a pickup device arranged to be able to detect a DPD signal while achieving a single spot push-pull method, and further to correspond to also an optical disk in which a plurality of signal layers exist.
2. Related Art
In recent years, optical disk drives (see, for example, Japanese Patent No. 3438160 (Patent Document 1) and JP-A-2004-281026 (Patent Document 2)) have remarkably been spread.
As a method of detecting a tracking error in such optical disk drives, a single spot push-pull method, for example, is disclosed in the Patent Document 1. Since this single spot push-pull method is a method having a simple configuration and higher efficiency of utilization of a laser beam in comparison with a three beam method, it is preferably used for a recordable optical disk drive.